Uncertainty in Genomics Impacts Precision Medicine.

As exacting as genetic and genomic testing have become, health professionals continue to encounter uncertainty in their applications to medical practice. As examining the human genome at more refined levels increases, so is the likelihood of encountering uncertainty about the meaning of the information. The history of this concept informs how we might confront and deal with uncertainty, and what the future might hold. Precision medicine holds great promise for establishing more accurate diagnoses, directing specific therapy to patients who will most benefit from it, and avoiding treatments in patients who are most likely to suffer adverse consequences, or at best not benefit. But its application depends importantly on the proper interpretation of a person's genotype.

Digital vascular lesions detected by transillumination.

Abnormalities of the capillaries of the digits in hereditary hemorrhagic telangiectasia can be detected by shining through a narrow beam of light through the dorsal side and visualizing the vasculature on the palmar side, a procedure termed transillumination. This study was performed to determine if this method can detect digital vascular abnormalities in aortopathies and arteriopathies. Transillumination was performed in patients with Marfan syndrome (MFS), thoracic aortic aneurysm and dissection (TAAD), vascular Ehlers-Danlos syndrome (vEDS), bicuspid aortic valve with aortopathy, and arteriopathies without aortopathy. Subjects with no known vascular disorders were controls. Digital vascular abnormalities were present in some patients with all of the disorders and were especially frequent in MFS, TAAD, and vEDS. All patients had significantly more digital vascular abnormalities than control subjects. Transillumination can detect vascular abnormalities in digits of patients with a variety of conditions with aortopathy or arteriopathy.

Arachnodactyly represented in art.

Arachnodactyly, a term used since 1902 to describe abnormally long (spider-like) fingers, is a pathologic feature of several heritable conditions, notably the Marfan syndrome and congenital contractural arachnodactyly. A number of prominent artists, dating from the 16th to the 20th centuries, have depicted subjects with unusually long fingers, sometime associated with elongation of the body, neck and head. El Greco incorporated this style in many paintings. Little evidence supports any subject in any of these paintings as having a congenital deformity.

Expanding the phenotypic spectrum of Mendelian connective tissue disorders to include prominent kidney phenotypes.

Heritable connective tissue disorders are a group of diseases, each rare, characterized by various combinations of skin, joint, musculoskeletal, organ, and vascular involvement. Although kidney abnormalities have been reported in some connective tissue disorders, they are rarely a presenting feature. Here we present three patients with prominent kidney phenotypes who were found by whole exome sequencing to have variants in established connective tissue genes associated with Loeys-Dietz syndrome and congenital contractural arachnodactyly. These cases highlight the importance of considering connective tissue disease in children presenting with structural kidney disease and also serves to expand the phenotype of Loeys-Dietz syndrome and possibly congenital contractural arachnodactyly to include cystic kidney disease and cystic kidney dysplasia, respectively.

Marfan syndrome: improved clinical history results in expanded natural history.

Life expectancy for a person with Marfan syndrome has essentially doubled over the past four decades. During this period, the clinical histories of the organs managed routinely have improved, and will continue to be. Prominent examples are the eyes, the heart and aorta, and some features of the skeletal system. Meanwhile, the natural histories of organ systems that have not been subjected to treatment need to be described. This is particularly important as due to the improved life span many symptoms and organ systems are only recently being recognized as being intrinsic to Marfan syndrome. Examples are the distal aorta and peripheral arteries, ventricular function, the central nervous system, sleep apnea, and adiposity. As a result, each person with Marfan syndrome will need to be evaluated and followed by more specialists than previously. Moreover, the coordinator of diagnostic testing and clinical referral must be aware of the expanded phenotype as people with Marfan syndrome age and the importance of life-long management of classical and novel features. The benefits of increased longevity and its consequences need to be addressed by investigators, health-care providers, and patients alike.

Health-Related Quality of Life in Children and Young Adults with Marfan Syndrome.

OBJECTIVE: To assess health-related quality of life (HRQOL) in a large multicenter cohort of children and young adults with Marfan syndrome participating in the Pediatric Heart Network Marfan Trial. STUDY DESIGN: The Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales were administered to 321 subjects with Marfan syndrome (5-25 years). PedsQL scores were compared with healthy population norms. The impact of treatment arm (atenolol vs losartan), severity of clinical features, and number of patient-reported symptoms on HRQOL was assessed by general linear models. RESULTS: Mean PedsQL scores in children (5-18 years) with Marfan syndrome were lower than healthy population norms for physical (P ≤ .003) and psychosocial (P < .001) domains; mean psychosocial scores for adults (19-25 years) were greater than healthy norms (P < .001). HRQOL across multiple domains correlated inversely with frequency of patient-reported symptoms (r = 0.30-0.38, P < .0001). Those <18 years of age with neurodevelopmental disorders (mainly learning disability, attention-deficit/hyperactivity disorder) had lower mean PedsQL scores (5.5-7.4 lower, P < .04). A multivariable model found age, sex, patient-reported symptoms, and neurodevelopmental disorder to be independent predictors of HRQOL. There were no differences in HRQOL scores by treatment arm, aortic root z score, number of skeletal features, or presence of ectopia lentis. CONCLUSIONS: Children and adolescents with Marfan syndrome were at high risk for impaired HRQOL. Patient-reported symptoms and neurodevelopmental disorder, but not treatment arm or severity of Marfan syndrome-related physical findings, were associated with lower HRQOL.

Genome sequencing reveals a deep intronic splicing ACVRL1 mutation hotspot in Hereditary Haemorrhagic Telangiectasia.

INTRODUCTION: Hereditary haemorrhagic telangiectasia (HHT) is a genetically heterogeneous disorder caused by mutations in the genes ENG, ACVRL1, and SMAD4. Yet the genetic cause remains unknown for some families even after exhaustive exome analysis. We hypothesised that non-coding regions of the known HHT genes may harbour variants that disrupt splicing in these cases. METHODS: DNA from 35 individuals with clinical findings of HHT and 2 healthy controls from 13 families underwent whole genome sequencing. Additionally, 87 unrelated cases suspected to have HHT were evaluated using a custom designed next-generation sequencing panel to capture the coding and non-coding regions of ENG, ACVRL1 and SMAD4. Individuals from both groups had tested negative previously for a mutation in the coding region of known HHT genes. Samples were sequenced on a HiSeq2500 instrument and data were analysed to identify novel and rare variants. RESULTS: Eight cases had a novel non-coding ACVRL1 variant that disrupted splicing. One family had an ACVRL1intron 9:chromosome 3 translocation, the first reported case of a translocation causing HHT. The other seven cases had a variant located within a ~300 bp CT-rich 'hotspot' region of ACVRL1intron 9 that disrupted splicing. CONCLUSIONS: Despite the difficulty of interpreting deep intronic variants, our study highlights the importance of non-coding regions in the disease mechanism of HHT, particularly the CT-rich hotspot region of ACVRL1intron 9. The addition of this region to HHT molecular diagnostic testing algorithms will improve clinical sensitivity.

Germline Loss-of-Function Mutations in EPHB4 Cause a Second Form of Capillary Malformation-Arteriovenous Malformation (CM-AVM2) Deregulating RAS-MAPK Signaling.

BACKGROUND: Most arteriovenous malformations (AVMs) are localized and occur sporadically. However, they also can be multifocal in autosomal-dominant disorders, such as hereditary hemorrhagic telangiectasia and capillary malformation (CM)-AVM. Previously, we identified RASA1 mutations in 50% of patients with CM-AVM. Herein we studied non-RASA1 patients to further elucidate the pathogenicity of CMs and AVMs. METHODS: We conducted a genome-wide linkage study on a CM-AVM family. Whole-exome sequencing was also performed on 9 unrelated CM-AVM families. We identified a candidate gene and screened it in a large series of patients. The influence of several missense variants on protein function was also studied in vitro. RESULTS: We found evidence for linkage in 2 loci. Whole-exome sequencing data unraveled 4 distinct damaging variants in EPHB4 in 5 families that cosegregated with CM-AVM. Overall, screening of EPHB4 detected 47 distinct mutations in 54 index patients: 27 led to a premature stop codon or splice-site alteration, suggesting loss of function. The other 20 are nonsynonymous variants that result in amino acid substitutions. In vitro expression of several mutations confirmed loss of function of EPHB4. The clinical features included multifocal CMs, telangiectasias, and AVMs. CONCLUSIONS: We found EPHB4 mutations in patients with multifocal CMs associated with AVMs. The phenotype, CM-AVM2, mimics RASA1-related CM-AVM1 and also hereditary hemorrhagic telangiectasia. RASA1-encoded p120RASGAP is a direct effector of EPHB4. Our data highlight the pathogenetic importance of this interaction and indicts EPHB4-RAS-ERK signaling pathway as a major cause for AVMs.

Covered Stents in the Treatment of Pulmonary Arteriovenous Malformations.

Seven patients with pulmonary arteriovenous malformations (PAVMs) not well suited to coil and/or plug treatment were treated with expanded polytetrafluoroethylene-covered stents. Mean diameter of treated arteries was 6 mm. Complete technical success was achieved in 7 of 8 PAVMs, 6 using only covered stents and 1 using both a covered and a bare stent owing to endoleak. In 1 patient, the parent vessel was sacrificed after identification of additional feeding vessels following stent graft placement. In 6 patients with median imaging follow-up of 8 months (range, 1-121 months), all stent grafts were patent, and all treated PAVMs were completely excluded without persistence.

Predictors of Rapid Aortic Root Dilation and Referral for Aortic Surgery in Marfan Syndrome.

Few data exist regarding predictors of rapid aortic root dilation and referral for aortic surgery in Marfan syndrome (MFS). To identify independent predictors of the rate of aortic root (AoR) dilation and referral for aortic surgery, we investigated the data from the Pediatric Heart Network randomized trial of atenolol versus losartan in young patients with MFS. Data were analyzed from the echocardiograms at 0, 12, 24, and 36 months read in the core laboratory of 608 trial subjects, aged 6 months to 25 years, who met original Ghent criteria and had an AoR z-score (AoRz) > 3. Repeated measures linear and logistic regressions were used to determine multivariable predictors of AoR dilation. Receiver operator characteristic curves were used to determine cut-points in AoR dilation predicting referral for aortic surgery. Multivariable analysis showed rapid AoR dilation as defined by change in AoRz/year > 90th percentile was associated with older age, higher sinotubular junction z-score, and atenolol use (R2 = 0.01) or by change in AoR diameter (AoRd)/year > 90th percentile with higher sinotubular junction z-score and non-white race (R2 = 0.02). Referral for aortic root surgery was associated with higher AoRd, higher ascending aorta z-score, and higher sinotubular junction diameter:ascending aorta diameter ratio (R2 = 0.17). Change in AoRz of 0.72 SD units/year had 42% sensitivity and 92% specificity and change in AoRd of 0.34 cm/year had 38% sensitivity and 95% specificity for predicting referral for aortic surgery. In this cohort of young patients with MFS, no new robust predictors of rapid AoR dilation or referral for aortic root surgery were identified. Further investigation may determine whether generalized proximal aortic dilation and effacement of the sinotubular junction will allow for better risk stratification. Rate of AoR dilation cut-points had high specificity, but low sensitivity for predicting referral for aortic surgery, limiting their clinical use. Clinical Trial Number ClinicalTrials.gov number, NCT00429364.

Atenolol versus losartan in children and young adults with Marfan's syndrome.

BACKGROUND: Aortic-root dissection is the leading cause of death in Marfan's syndrome. Studies suggest that with regard to slowing aortic-root enlargement, losartan may be more effective than beta-blockers, the current standard therapy in most centers. METHODS: We conducted a randomized trial comparing losartan with atenolol in children and young adults with Marfan's syndrome. The primary outcome was the rate of aortic-root enlargement, expressed as the change in the maximum aortic-root-diameter z score indexed to body-surface area (hereafter, aortic-root z score) over a 3-year period. Secondary outcomes included the rate of change in the absolute diameter of the aortic root; the rate of change in aortic regurgitation; the time to aortic dissection, aortic-root surgery, or death; somatic growth; and the incidence of adverse events. RESULTS: From January 2007 through February 2011, a total of 21 clinical centers enrolled 608 participants, 6 months to 25 years of age (mean [±SD] age, 11.5±6.5 years in the atenolol group and 11.0±6.2 years in the losartan group), who had an aortic-root z score greater than 3.0. The baseline-adjusted rate of change in the mean (±SE) aortic-root z score did not differ significantly between the atenolol group and the losartan group (-0.139±0.013 and -0.107±0.013 standard-deviation units per year, respectively; P=0.08). Both slopes were significantly less than zero, indicating a decrease in the aortic-root diameter relative to body-surface area with either treatment. The 3-year rates of aortic-root surgery, aortic dissection, death, and a composite of these events did not differ significantly between the two treatment groups. CONCLUSIONS: Among children and young adults with Marfan's syndrome who were randomly assigned to losartan or atenolol, we found no significant difference in the rate of aortic-root dilatation between the two treatment groups over a 3-year period. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT00429364.).

Chronobiology of Acute Aortic Syndromes.

Acute aortic syndromes are highly morbid conditions that require prompt diagnosis and management. Aortic dissections have rhythmic patterns, with notable peaks at certain points in every 24 hours as well as weekly and seasonal variations. Several retrospective studies have assessed the chronobiology of acute aortic dissections and there seems to be a winter seasonal peak and morning daily peak in incidence. Although the pathophysiology of this chronobiology is unclear, there are several environmental and physiologic possibilities. This article reviews the major studies examining the chronobiology of acute aortic dissection, and summarizes some theories on the pathophysiology of this phenomenon.

Shock complicating type A acute aortic dissection: Clinical correlates, management, and outcomes.

AIMS: Shock is among the most dreaded and common complications of type A acute aortic dissection (TAAAD). However, clinical correlates, management, and short- and long-term outcomes of TAAAD patients presenting with shock in real-world clinical practice are not known. METHODS AND RESULTS: We evaluated 2,704 patients with TAAAD enrolled in the International Registry of Acute Aortic Dissection between January 1, 1996, and August 18, 2012. On admission, 407 (15.1%) TAAAD patients presented with shock. Most in-hospital complications (coma, myocardial or mesenteric ischemia or infarction, and cardiac tamponade) were more frequent in shock patients. In-hospital mortality was significantly higher in TAAAD patients with than without shock (30.2% vs 23.9%, P=.007), regardless of surgical or medical treatment. Most shock patients underwent surgical repair, with medically managed patients demonstrating older age and more complications at presentation. Estimates using Kaplan-Meier survival analysis indicated that most (89%) TAAAD patients with shock discharged alive from the hospital survived 5years, a rate similar to that of TAAAD patients without shock (82%, P=.609). CONCLUSIONS: Shock occurred in 1 of 7 TAAAD patients and was associated with higher rates of in-hospital adverse events and mortality. However, TAAAD survivors with or without shock showed similar long-term mortality. Successful early and aggressive management of shock in TAAAD patients has the potential for improving long-term survival in this patient population.

Effect of Topical Intranasal Therapy on Epistaxis Frequency in Patients With Hereditary Hemorrhagic Telangiectasia: A Randomized Clinical Trial.

IMPORTANCE: Epistaxis is a major factor negatively affecting quality of life in patients with hereditary hemorrhagic telangiectasia (HHT; also known as Osler-Weber-Rendu disease). Optimal treatment for HHT-related epistaxis is uncertain. OBJECTIVE: To determine whether topical therapy with any of 3 drugs with differing mechanisms of action is effective in reducing HHT-related epistaxis. DESIGN, SETTING, AND PARTICIPANTS: The North American Study of Epistaxis in HHT was a double-blind, placebo-controlled randomized clinical trial performed at 6 HHT centers of excellence. From August 2011 through March 2014, there were 121 adult patients who met the clinical criteria for HHT and had experienced HHT-related epistaxis with an Epistaxis Severity Score of at least 3.0. Follow-up was completed in September 2014. INTERVENTIONS: Patients received twice-daily nose sprays for 12 weeks with either bevacizumab 1% (4 mg/d), estriol 0.1% (0.4 mg/d), tranexamic acid 10% (40 mg/d), or placebo (0.9% saline). MAIN OUTCOMES AND MEASURES: The primary outcome was median weekly epistaxis frequency during weeks 5 through 12. Secondary outcomes included median duration of epistaxis during weeks 5 through 12, Epistaxis Severity Score, level of hemoglobin, level of ferritin, need for transfusion, emergency department visits, and treatment failure. RESULTS: Among the 121 patients who were randomized (mean age, 52.8 years [SD, 12.9 years]; 44% women with a median of 7.0 weekly episodes of epistaxis [interquartile range {IQR}, 3.0-14.0]), 106 patients completed the study duration for the primary outcome measure (43 were women [41%]). Drug therapy did not significantly reduce epistaxis frequency (P = .97). After 12 weeks of treatment, the median weekly number of bleeding episodes was 7.0 (IQR, 4.5-10.5) for patients in the bevacizumab group, 8.0 (IQR, 4.0-12.0) for the estriol group, 7.5 (IQR, 3.0-11.0) for the tranexamic acid group, and 8.0 (IQR, 3.0-14.0) for the placebo group. No drug treatment was significantly different from placebo for epistaxis duration. All groups had a significant improvement in Epistaxis Severity Score at weeks 12 and 24. There were no significant differences between groups for hemoglobin level, ferritin level, treatment failure, need for transfusion, or emergency department visits. CONCLUSIONS AND RELEVANCE: Among patients with HHT, there were no significant between-group differences in the use of topical intranasal treatment with bevacizumab vs estriol vs tranexamic acid vs placebo and epistaxis frequency. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01408030.

Stroke and outcomes in patients with acute type A aortic dissection.

BACKGROUND: Stroke is a highly dreaded complication of type A acute aortic dissection (TAAAD). However, little data exist on its incidence and association with prognosis. METHODS AND RESULTS: We evaluated 2202 patients with TAAAD (mean age 62 ± 14 years, 1487 [67.5%] men) from the International Registry of Acute Aortic Dissection to determine the incidence and prognostic impact of stroke in TAAAD. Stroke was present at arrival in 132 (6.0%) patients with TAAAD. These patients were older (65 ± 12 versus 62 ± 15 years; P=0.002) and more likely to have hypertension (86% versus 71%; P=0.001) or atherosclerosis (29% versus 22%; P=0.04) than patients without stroke. Chest pain at arrival was less common in patients with stroke (70% versus 82%; P<0.001), and patients with stroke presented more often with syncope (44% versus 15%; P<0.001), shock (14% versus 7%; P=0.005), or pulse deficit (51% versus 29%; P ≤ 0.001). Arch vessel involvement was more frequent among patients with stroke (68% versus 37%; P<0.001). They had less surgical management (74% versus 85%; P<0.001). Hospital stay was significantly longer in patients with stroke (median 17.9 versus 13.3 days; P<0.001). In-hospital complications, such as hypotension, coma, and malperfusion syndromes, and in-hospital mortality (adjusted odds ratio, 1.62; 95% confidence interval, 0.99-2.65) were higher among patients with stroke. Among hospital survivors, follow-up mortality was similar between groups (adjusted hazard ratio, 1.15; 95% confidence interval, 0.46-2.89). CONCLUSIONS: Stroke occurred in >1 of 20 patients with TAAAD and was associated with increased in-hospital morbidity but not long-term mortality. Whether aggressive early invasive interventions will reduce negative outcomes remains to be evaluated in future studies.

Heritable thoracic aortic disorders.

PURPOSE OF REVIEW: Disease of the wall of the thoracic aorta has many causes: inflammation, infection and atherosclerosis are the most common 'acquired' causes, but even these have genetic predispositions. This article deals with aortic disease due to mutations in specific genes. The conditions can affect tissues and organs other than the aorta (syndromic) or be limited to the aorta (nonsyndromic). RECENT FINDINGS: A classification scheme based on the gene is emerging, those that affect primarily the extracellular matrix (e.g., FBN1, COL3A1), TGF-ß signaling (e.g., TGFBR1, TGFB2), or vascular smooth muscle cell contractility (e.g., ACTA2, MYH11). SUMMARY: Understanding pathogenesis is driving the development of novel therapies, such as angiotensin receptor blockade, which is in clinical trial. However, recurrent imaging, restriction of exercise, ß-adrenergic blockade, and prophylactic surgery remain effective in preventing dissection and sudden death.

A qualitative study of healthcare providers' perspectives on the implications of genome-wide testing in pediatric clinical practice.

The utilization of genome-wide chromosomal microarray analysis (CMA) in pediatric clinical practice provides an opportunity to consider how genetic diagnostics is evolving, and to prepare for the clinical integration of genome-wide sequencing technologies. We conducted semi-structured interviews with 15 healthcare providers (7 genetic counselors, 4 medical geneticists, and 4 non-genetics providers) to investigate the impact of CMA on clinical practice, and implications for providers, patients and families. Interviews were analyzed qualitatively using content analysis. Most providers reported that genomic testing enhanced their professional experience and was beneficial to patients, primarily due to the improved diagnostic rate compared with earlier chromosomal studies. Other effects on practice included moving towards genotype-first diagnosis and broadening indications for chromosomal testing. Opinions varied concerning informed consent and disclosure of results. The duty to disclose incidental findings (IFs) was noted; however concerns were raised about potential psychosocial harms of disclosing pre-symptomatic findings. Tensions were revealed between the need for comprehensive informed consent for all families and the challenges of communicating time-consuming and potentially anxiety-provoking information regarding uncertain and incidental findings that may be relevant only in rare cases. Genetic counselors can play an important role in liaising with families, health professionals and testing laboratories, providing education and guidance to non-genetics providers, and enabling families to receive adequate pre-and post-test information and follow-up care.